While we don't know how local communication equipment (like a speeder bike's) works, we can make assumptions. Point-to-point light transmissions, such as those performed via laser beams (or fiber-optic cable), require a cable or a direct line-of-sight, which isn't practical for use on a planet's surface. Other communication methods are unlikely to have the speed or sensitivity to be useful.
That leaves us with some form of radio or microwave transmission. As we we already have the ability to disrupt these, the higher-tech Star Wars universe can be expected to handle this just as easily as the EU and movies show.
For ship-to-ship and other interstellar communication, this becomes more difficult to guess. The Holonet itself is never really explained, but it has a physical requirement, as the Yuuzhan Vong destroy much of it. Ships tapping into the 'net must send messages first to these satellites/outposts/facilities/deep-space buoys.
As light travels much faster than microwaves, I'll assume they use it in space. This kind of communication would be much more difficult to stop en-route. However, you could overload the receiver. Assuming the Holonet buoy has a tight-beam light receiver, and your ship wants to talk to it, I could send a constant beam of light at the receiver to prevent it from understanding your message (a "denial of service" jam). Assuming my power source is at least as powerful as yours, or assuming I can actually burn out the receiver itself so no communication can take place, this should work.
Alternatively, if I have access to the Holonet receiver itself, either through hacking or secure access (as the Empire would have had), I could simply shut it down. That would stop all faster-than-light communication methods without further hassle.
Stopping light-speed ship-to-ship communication inside a planetary system would be difficult, as ships tend to move. In the short term, however, it would work. If the target ship is across the system, light would take hours to reach it. An example: I jam the target's receptors, you send a message, I destroy your ship, my jam reaches the target, your message reaches them but they can't see it because of the jam, they react to the jam by moving their ship, but you are already dead and cannot re-send the message to the new location of the ship.
All of this assumes the Star Wars universe uses technology we have envisioned as of now. If ships themselves mount Holonet-capable devices and can use them to communicate with nearby Holonet buoys, then any guesswork on the theory is out the window. We simply don't know enough about how the Holonet works.
